Stability Analysis of Horizontal Layered Multi-Stage Fill Slope Based on Limit Equilibrium Method

The stability of a multi-stage fill slope composed of horizontal layered soil is particularly prominent due to its complex structural characteristics, the variability of filler properties, and the combined effects of external environmental factors. Therefore, it is of great significance to clarify whether such slopes are in a safe state. Based on the limit equilibrium method, this paper divides the soil horizontally and obliquely and analyzes the stress and establishes the potential failure mechanism (such as slope toe circle, midpoint circle, etc.) of the multi-stage fill slope in the overall failure mode and local failure mode. The analytical expressions of slope safety factors corresponding to various failure mechanisms are further derived, and the stability analysis process of multi-stage fill slope and the determination method of the most dangerous slip surface are proposed. Through the verification of two examples, the results show that the safety factor obtained by this method is similar to the minimum safety factor obtained by the traditional slice method, and the error is small. At the same time, the most dangerous slip surface and slip range are basically consistent with the traditional method. The research results can provide a theoretical basis and practical reference for stability analysis, filler selection, and engineering design of the fill slope.